Alloy

A substance that has metallic properties and is composed of two or more chemical elements of which at least one is an elemental metal.

Source: The OHIO State University

An alloy is a partial or complete solid solution of one or more elements in a metallic matrix. Complete solid solution alloys give single solid phase microstructure, while partial solutions give two or more phases that may be homogeneous in distribution depending on thermal (heat treatment) history. Alloys usually have different properties from those of the component elements.

Source: Wikipedia